The present invention relates to an image sensing apparatus and, more particularly, to an image sensing apparatus which senses an image by using a non-interlace or progressive scanning type image sensing device.
As digital signal processing technique improves, many image sensing apparatuses, such as a video camera, having an image sensing unit and a digital recording and playing unit have been developed.
In those apparatuses, standard video signals are generated by an image sensing unit provided with an image sensing device, such as a CCD, compressed by discrete cosine transform (DCT) and quantization, then the compressed video signals are encoded in a format which is suitable for digital tape recording. Thereafter, the encoded signals are recorded on a tape by a recording head. Upon playing back the tape, errors of reproduced signals read by a real head are corrected, decoded and expanded in an opposite manner to the recording operation, then outputted as reproduced video signals.
An example of an image sensing apparatus is shown in FIG. 27.
In FIG. 27, reference numeral 1001 denotes a lens; 1002, a CCD as an interlace scanning type image sensing device for converting an optical image of an object into electrical signals; 1003, an A/D converter for converting analog signals into digital signals; 1004, a camera signal processing circuit for converting the digitized output of the CCD 1002 into video signals of a unit of field; 1005, a video signal processing circuit for compressing the video signals and transforming the compressed video signals to recording data in a format which is suitable for magnetic recording; 1006, a recording circuit for magnetically recording the recording data on a magnetic tape or the like; 1007, a CCD driver for controlling timing of driving the CCD 1002; 1008, an image memory for storing image data; and 1009, a memory address controller for controlling write/read addresses for writing/reading image data to/from the image memory 1008.
An optical image of the object which passed through the lens 1001 is converted into electrical signals of field, which is composed of odd lines or even lines, by the CCD 1002. The output from the CCD 1002 is converted into digital signals by the A/D converter 1003, then enters the camera signal processing circuit 1004. The camera signal processing circuit 1004 performs aperture correction, high luminance color knee correction, white balance correction, xcex3 correction, matrix operation, addition of a synchronization signal, AF preprocessing, AE preprocessing, and so on. Then, it outputs luminance signals and time division multiplexed color difference signals of two kinds of color difference signals by interlaced field. These luminance signals and time division multiplexed color difference signals enter the video signal processing circuit 1005.
The video signal processing circuit 1005 generates frame image data from image data of two successive fields by using the image memory 1008 controlled by the memory address controller 1009, then divides the frame image data into image data of blocks. Thereafter, the image data of blocks is applied with shuffling process in which image data of blocks is read out in a order that is suitable for progressive coding, orthogonal transform, such as DCT, for transforming the read image data of blocks into orthogonal transform coefficients, quantization for quantizing the orthogonal transform coefficients of block depending upon skew of the orthogonal transform coefficients, such as DCT coefficients, to a low frequency range or to a high frequency range, thereby reducing the amount of data, and coding process for further reducing the amount of data by using Huffman coding, for example.
Further, de-shuffling process for de-shuffling the shuffled and quantized data of blocks is performed by using the image memory 1008 controlled by the memory address controller 1009. Thereby, the luminance signals and the color difference signals are transformed into coded data whose amount is compressed.
Furthermore, the video signal processing circuit 1005 converts the coded data into recording data in a form suitable for magnetic recording, and the recording data is inputted into the recording circuit 1006, then recorded on a magnetic medium.
Most of image sensing devices, such as a CCD, used in a general-use video camera as described above, are composed of a great many number of photoelectric converters (pixels) arranged in two dimensions and a mechanism for sequentially transferring electric charges generated in the photoelectric converters. Upon transferring the electric charges, electric charges generated in the photoelectric converters in every other horizontal line are read out. Therefore, image signals of a half of the pixels in the image sensing device are outputted as image signals of each field in order to improve time division resolution. As for an image sensing device whose surface is covered with a complementary color mosaic filter, electrical charges of pixels in two horizontal adjacent lines are added and read out upon transferring electric charges generated by the photoelectric converters, thereby improving time division resolution as well as sensitivity.
The image signals obtained from the image sensing device as described above are interlaced signals, and a conventional general-use image sensing apparatus applies color conversion, and the like, on the image signals from the image sensing device to generate video signals which agree to television standard, such as NTSC and PAL.
Meanwhile, there is a proposal to output image signals generated by a two dimensional image sensing device as a moving image to a television monitor of television standard, such as NTSC and PAL, as well as output the image signals to an information processing device, such as a computer and a printer, as a still image.
However, image signals which are generated in a conventional manner as described above do not have good vertical resolution since it is sacrificed for improving time division resolution. Therefore, the quality of an image of a field inferiors to the quality of an image inputted by a still image input device, such as a scanner. In a case of printing the image of a field by a video printer or using it as an input image in a computer, since horizontal resolution of the image is much different from vertical resolution of the image, each pixel of the image has a shorter width and a longer length, thereby the obtained image may be blurred and give an unnatural impression. Especially, when the image of a field is directly dealt with by a computer, since the computer deals with each pixel as a square dot, a resulted image will have a rectangular shape having longer sides. Therefore, an image of a field has to be processed, however, the processed image would be of inferior quality.
If an image of an even field and an image of a successive odd field are combined together to make a frame image in order to avoid the aforesaid problem, when an object is moving, the combined frame image would not be a still image of high quality since the object looks differently when sensing an image of the even field and when sensing an image of the odd field. Further, when image signals of a field are obtained by adding electric charges of pixels in two horizontal adjacent lines (pixel addition reading method), vertical resolution is also deteriorated. Accordingly, resolution of a frame image obtained by combining an image of an odd field and an image of a successive even field does not improve. Furthermore, when the combined image is printed by a video printer, the printed image looks unnatural since the resolution in the horizontal direction and that in the vertical direction quite differ from each other, which causes blurring of each pixel in the vertical direction.
In an image sensing apparatus using a conventional image sensing device which read out image signals by adding charges of pixels in two horizontal adjacent lines, as described above, it is difficult to generate video signals of various kinds of television standard and signals for a still image of high quality to be outputted from a still image output medium by using a single image sensing apparatus.
Furthermore, in a case where an image sensing device which reads all of the light receiving pixels by so-called non-interlace or progressive scanning is used, outputted image signals have a format different from that of standard television signals. Accordingly, there is a problem in which the output signals from the image sensing device can not be outputted on an electronic view finder (EVF) or a television monitor.
Further, a general video printer is designed so as not to accept non-standard television signals, therefore image signals outputted from the image sensing device which reads all of the light receiving pixels by non-interlace scanning can not be printed out directly.
The present invention has been made in consideration of above situation, and has as its object to provide an image sensing apparatus capable of obtaining a still image of high resolution by improving vertical resolution by using an image sensing device which is used for sensing both a moving image and a still image.
According to the present invention, the foregoing object is attained by providing an image sensing apparatus comprising: image sensing means for outputting data of all of light receiving pixels in a field period; first separation means for separating data of pixels on every other horizontal line out of the data of all of the light receiving pixels outputted by the image sensing means and generating first image data; second separation means for separating data of pixels on every other horizontal line which is not separated by the first separation means and generating second image data; selection means for selecting one of a plurality of modes which set different processes from each other to be performed on the first image data and the second image data; and storage means for storing the first image data and the second image data, wherein the first separation means separates data of every other horizontal line which is different from horizontal lines from which data are read in a previous field period.
The foregoing object is also attained by providing an image sensing apparatus comprising: image sensing means for outputting data of all of light receiving pixels in a field period; first output means for alternatively outputting data of pixels in two different fields out of the data of all of the light receiving pixels outputted from the image sensing means by a field period; and second output means for outputting the data of all of the light receiving pixels outputted from the image sensing means in every other field period.
The foregoing object is also attained by providing an image sensing apparatus comprising: image sensing means for outputting data of all of light receiving pixels in a field period; a color filter provided in front of the image sensing means; first output means for adding data of pixels, outputted from the image sensing means, on two horizontal adjacent lines whose combination in a field period is different from that in a previous field period and outputting the added data; and second output means for outputting the data of all of the light receiving pixels outputted from the image sensing means in every other field period.
According to the configuration as described above, when sensing a moving image, image signals of a frame, outputted from CCD, in every other line are used or image signals of pixels in two adjacent lines are added to make a field, and image signals of the next field are obtained by using image signals in every other line which has not been used in a previous frame in the former case or by adding image signals of pixels in different combination of two adjacent lines in the latter case. In the aforesaid manner, field images are generated and applied with predetermined processes sequentially. Further, the obtained image signals are processed and outputted as various kinds of television standard video signals. In a case of outputting the image signals as a still image, all the signals of a frame outputted by the non-interlace scanning type CCD are processed and outputted, thereby obtaining a still image of high quality using the vertical resolution of the non-interlace scanning type CCD direction at 100%.
It is another object of the present invention to provide an image sensing apparatus which avoids performing redundant signal processes when sensing a moving image by using an image sensing device which scans all of the light receiving pixels sequentially.
The foregoing object is attained by providing an image sensing apparatus comprising: image sensing means for outputting data of all of light receiving pixels in a field period; processing means for processing the data of all of the light receiving pixels outputted from the image sensing means; and control means for controlling the processing means so as to separate data of pixels on every other horizontal line out of the data of all of the light receiving pixels outputted by the image sensing means to generate moving image data.
According to the aforesaid configuration, since either image signals in the odd lines or image signals in the even lines are alternatively selected from successive different frame images to generate signals for a moving image, image signals in either even or odd lines which are not selected are not processed in vain, thereby saving energy.
It is still another object of the present invention to provide an image sensing apparatus capable of recording a still image of high quality without notches on outlines, as well as capable of dealing with obtained image signals in the same manner as general standard television signals.
According to the present invention, the foregoing object is attained by providing an image sensing apparatus comprising: image sensing means for outputting data of all of light receiving pixels by non-interlace scanning; storage means for storing the data of all of the light receiving pixels outputted from the image sensing means; and reading means for reading the data stored in the storage means in interlaced form.
With the configuration as described above, it is possible to sequentially write signals outputted by non-interlace scanning in a frame memory as well as read the stored signals in interlaced form and output to an external device. Accordingly, it is possible to effectively use all of the image data of a frame outputted by the non-interlace scanning type image sensing means, and to generate image signals, which can be displayed on an electronic view finder and a general-use television, of an image under recording or an image to be recorded.
According to an aspect of the present invention, one of the reading means and the recording processing means reads the data stored in the storage means.
With the aforesaid configuration, a reading unit is configured so as not to operate when recording an image, thus, the reading operation of reading image signals stored in the frame memory in the interlaced form is not performed during recording. Thereby, it is possible to record a still image as well as monitor a still image to be recorded without a high-speed memory.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.